Field of the Invention
The invention relates to an exhaust valve assembly for a bottle attachment apparatus for handling liquids, to an exhaust line assembly, to a valve block assembly, and to a bottle attachment apparatus for handling liquids.
Description of Related Art
In the case of bottle attachment apparatuses for handling liquids, the focus is on precisely measuring and conveying liquids from a storage bottle or another storage container, wherein precise measuring is performed when a partial volume of liquid is received from the storage bottle or similar into the apparatus and/or when a partial volume of liquid is externally dispensed from the apparatus into a container.
Bottle attachment apparatuses of the type being discussed are in particular bottle attachment dispensers and burettes. Bottle attachment apparatuses of this type are widely used in chemical, biological, and pharmaceutical laboratories and production facilities.
The term “liquid” in the present context preferably refers to liquids as are used in chemical, biological, and pharmaceutical laboratories and production facilities etc. These are preferably liquids having a relative viscosity of up to about 300 (viscosity relative to the viscosity of water, measured at normal conditions). In colloquial terms, the liquids are thus preferably those in the range of very low viscosity to slightly viscous.
In the case of bottle attachment apparatuses of the type being discussed, high requirements are set for volume accuracy of liquid intake and/or liquid dispensation, and for operator safety. The bottle attachment apparatuses are usually operated manually or are driven by an actuator.
A typical example of a bottle attachment apparatus in the form of a bottle top dispenser is known from European Patent Application EP 0 542 241 A2. The present invention proceeds from this prior art. For bottle attachment apparatus in the form of bottle top dispensers, reference is made to European Patent Application EP 0 542 241 A2, the entire content of which is hereby incorporated by reference.
In an exemplary manner, a bottle attachment apparatus in the form of a buret is known from European Patent Application EP 2 799 141 A2 and corresponding U.S. Pat. No. 8,142,738 B2. A bottle attachment apparatus in the form of burette has many construction details in common with a bottle attachment apparatus in the form of a bottle top dispenser. Also to this extent, reference is made to European Patent Application EP 2 799 141 A2 and corresponding U.S. Pat. No. 8,142,738 B2 the entire extent content of which is hereby incorporated by reference.
Here and hereunder, a bottle attachment apparatus is always described in the operating position thereof, that is to say in the position thereof when fastened to a storage bottle or similar, and when aligned in a substantially vertical manner. A valve block assembly for such a bottle attachment apparatus is also described in a corresponding manner, that is to say likewise in the operating position thereof, that is to say when installed in a bottle attachment apparatus in the operating position thereof.
A substantial component part of a bottle attachment apparatus of the type being discussed is the cylinder-and-piston assembly with the aid of which the liquid may be suctioned and exhausted again. The cylinder-and-piston assembly has a cylinder which defines a longitudinal direction, and a piston which is guided in a sealed manner in the cylinder so as to be longitudinally displaceable. The direction of movement of the piston in the operating position of the bottle attachment apparatus is oriented so as to be vertical, in the following thus defining the vertical direction.
In the event of an upward movement of the piston in the cylinder, the liquid is suctioned by forming negative pressure in the cylinder. In the event of a downward movement, the liquid in the cylinder is exhausted again from the cylinder. The flow of the liquid during suctioning, on the one hand, and during exhausting, on the other hand, is directed by valves of the valve block assembly. The cylinder-and-piston assembly is connected in a sealing manner to the valve block assembly and to the lines which are located therein. The valve block assembly as such in turn is attached onto the storage bottle or similar with the aid of a fastening assembly.
An intake valve which allows liquid to be suctioned from the storage bottle by means of an intake pipe is located in the valve block of the valve block assembly. The intake pipe, most often in the form of a plug-fitted tube, extends deeply downward into the storage bottle. An exhaust line extends away from the valve block in an approximately horizontal manner. An exhaust valve sits in the exhaust line or in the valve block, so as to be at the beginning of the exhaust line. In some instances, an additional switching valve by way of which a return flow line leading back into the storage bottle may be opened or closed sits so as to be upstream of the exhaust line.
At the opening from which the liquid exits, the exhaust line may have a closure.
Since the exhaust line protrudes from the valve block in an approximately horizontal manner and the previously discussed switching valve also often sits there, this is the side from where an operator works on the bottle attachment apparatus. This side may be referred to as the “front side” of the bottle attachment apparatus. The opposite side is the “rear side” of the bottle attachment apparatus. In the case of an electronic design embodiment of a bottle attachment apparatus, a display having corresponding operating elements is preferably located on the front side of the bottle attachment apparatus.
The fastening assembly for fastening the external housing and/or the valve block assembly of the bottle attachment apparatus onto a storage bottle or similar is often a thread assembly which is similar to a union nut, or is an internal thread which is incorporated into the valve block per se, for screwing onto the external thread on a bottleneck of the storage bottle (see the prior art mentioned at the outset). However, in principle other fastening assemblies, such as bayonet systems or short-stroke collets are likewise employable, as are systems of the type of a taper-ground joint, which are usual in laboratories.
The present focus is on the region of the exhaust valve in the context of an exhaust valve assembly for a bottle attachment apparatus of the type being discussed, but also the further region downstream of the exhaust valve, that is to say in the region of an exhaust line assembly including the exhaust line, up to the tip thereof.
In the prior art from which the present invention proceeds (German Patent Application DE 36 07 139 A1), a respective exhaust valve assembly comprises a valve housing which forms a valve chamber having a inlet and an outlet. An exhaust valve body, which together with an exhaust valve seat which is likewise disposed there collectively forms the exhaust valve, is disposed on the inlet in the valve chamber. An additional safety valve body, which together with a safety valve seat which is disposed on the outlet forms an additional safety valve, is located at the outlet of the valve chamber of the valve housing. The safety valve has the task of preventing liquid from inadvertently leaking when the connector end of the exhaust line is pulled away from the exhaust valve assembly.
The connector end of the exhaust line, counter to a spring force, lifts the safety valve body from the safety valve seat at the outlet of the valve housing of the exhaust valve assembly and opens the flow path into the exhaust line. The connector end at the end side is provided in an encircling manner with preferably a plurality of openings, such that the liquid which flows around the valve body of the safety valve which has been lifted from the valve seat may radially flow into the connector end. For details of this construction reference is made to German Patent Application DE 36 07 139 A1.
In the case of the known exhaust valve assembly, the safety valve seat for the safety valve body is disposed on a valve bushing which is inserted in a sealing manner at the outlet of the valve housing. Sealing between this valve bushing and the valve housing is at times an issue. Moreover, the entry point of the connector end of the exhaust line is a region which is problematic in terms of leakages. Here, bending momemtums which contribute to the connector end occasionally being loosened in the outlet of the valve housing arise during handling.
Downstream of the exhaust valve, a bottle attachment apparatus of the type being discussed has an exhaust line assembly. The exhaust line assembly includes at least the exhaust line, preferably also a mount supporting the exhaust line, and moreover in the case of a bottle attachment apparatus having return dosing, the switching valve which has been discussed in detail at the outset. If a switching valve is present, the exhaust line is connected downstream to the switching valve, while a connector end which is plug-fittable into the outlet of the valve housing or is push-fittable onto said outlet, and a return flow connector which is plug-fittable into a return flow inlet of the valve block or is push-fittable onto said return flow inlet are disposed on the switching valve, so as to be upstream thereof. So in the prior art the exhaust line assembly of a bottle attachment apparatus having a switching valve looks different from the exhaust line assembly in the case of a bottle attachment apparatus without a switching valve.